1. Field of the Invention
This invention relates to fluid conductors and more particularly a valve interposed in a fluid flow line for monitoring fluid flow velocity.
2. Description of the Prior Art
The most pertinent patent is believed to be U.S. Pat. No. 5,067,511, issued Nov. 26, 1991, to Taylor for High Pressure Emergency Fluid Shutoff Valve.
This patent discloses a valve body having a flow passage way interposed in a fluid conducting line. A valve having a head portion substantially greater in diameter than it's stem portion slidably supported by the valve body. The valve head is normally maintained unseated in an upstream direction by a collapsible pin axially interposed between a valve cage and the end of the valve stem opposite it's head. In the event the downstream end of the flow line is closed, pressure built up in the valve body flow passageway forces the valve closed by collapsing the pin.
This invention similarly discloses a valve body having a flow passageway interposed in a fluid flow line, in which a valve is maintained off it's seat by a collapsible pin interposed between a valve cage and the end of the valve stem opposite it's head. Fluid flowing against the valve head above predetermined flow rate biases the valve head to a passageway closed position by the flow pressure acting on the valve stem cross sectional area and causing an axial force on the pin, collapsing the pin and moving the valve stem in a downstream direction.